In Tables 16.7 and 16.8, T.38 fax bit rates are listed for basic fax rates and redundancies. In Table 16.7, bit rates are presented for no redundancy (R0) and 3-times redundancy (R3) on an Ethernet interface. The details on various headers [URL (National-Eth)] and their meaning are given in Chapter 11. For any other redundancy, the row marked “UDPTL, IFP, error recovery, redundancy” has to be changed with the corresponding values given in Table 16.6 for different redundancies.
On a DSL interface, the bit rate increases because of the additional header of PPPoE [Mamakos et al. (1999)], AAL5 trailer header, ATM cell splitting, and zero padding as shown in Table 16.8. More details on the headers are given in Chapter 11 for calculating the voice bit rate. A summary on T.38 bit rate requirements for Ethernet and DSL interfaces are given below: